White-flesh guava juice clarification by a fixed-angle conical rotor centrifuge laboratory and characterization of continuous disk stack centrifuges

The two objectives of this paper were to determine the effect of centrifugation parameters on guava juice physicochemical characteristics and to identify operational characteristics of continuous disc-stack centrifuges based on the performance of a laboratory centrifuge. Effects of g-force (149 g–3731 g) and centrifugation time (10–40 min) on juice physicochemical characteristics (protein, pectin, galacturonic acid, dry matter, total soluble sugars contents; pH; electrical conductivity, clarity and particle size distribution) were assessed. Laboratory centrifuge performance was evaluated for 1343 g, 2388 g and 3731 g. At 1343 g, separation limits (x(max)), feed flow-rates of disc-stack centrifuges and cut-off sizes (x(50)) were determined for corresponding laboratory centrifuge operation times. Significant decrease in average particle size, protein and pectin contents was observed, contrary to juice clarity. Similar clarification efficiency was obtained for g-forces ≥ 1343 g. x(max) were 2669 nm, 2200 nm and 1783 nm, with corresponding x(50) for continuous centrifuges, 1887 nm, 1556 nm, 1261 nm, for 20 min, 30 min and 40 min, respectively.